Alloy steel



Patented Feb. 15, 1927.

UNITED STATES PATENT OFFICE.

CHARLES MORRIS JOHNSON, OF AVALON, PENNSYLVANIA, ASSIQNOR TO CBUCIBLE STEEL COMPANY OF AMERICA, A CORPORATION OF NEw JERSEY.

ALLOY STEEL.

No Drawing.

In United States Letters Patents heretofore 'rranted to me, No. 1,420,707 and No. 1,420,408. both dated June 27th, 1922, I have described and claimed certain allov steels containing chromium, nickel and silicon in amounts therein set forth, raid steels being highly resistant to corrosion and pose2sing advantageous mechanical qualities as well.

The present invention resides in an im- 1 proved steel for the same general purposes, dilfering mainly in that it has a distinctly higher chromium content. with preferably a small amount of vanadium in addition. Steel of the composition herein described has been found by me to be more resistant to substances met with in industry generally thanthe compositions described in my prior patent (except perhaps only in the care of sulphuric acid). It also has the highest resistance of any to oxidation at high temperatures.

The preferred composition of this im proved steel is chromium 25.50% to 26.50%, nickel 24.50% to 25.50%, silicon 1% to 3.50% and Vanadium 0.10% to 0.30%. It may contain manganese up to about 0.65%, and for the best results the carbon content should not materially exceed 0.30%.

Some variation from this preferred comosition however may be made without greaty affecting the essential qualities of the steel.

Application filed June 27, 1925. Serial No. 40,101.

For example the chromium content may vary from 25% to 30%, and the nickel from 20% to 30%, while. as well known, the carbon may be higher, though it should not exceed 1%. g

It is well known that nickel and cobalt have many like chemical properties, andthat their metallurgical effects in alloy steel are generally alike, so I desire it to be understood that by the appended claims I intend to cover the use of cobalt as a substitute for nickel in whole or in part.

As will also be well understood, other 211- loying metals may be employed in minor percentages, as, for example, tungsten up to four or five per cent.

I claim as my invention:

1. Steel containing from about twentyfive per cent to about thirty per cent of chromium, from about twenty per c'entto about thirty per cent of nickel, and from about one per cent to. about three and onehalf per cent of silicon.

2. Steel containing chromium and nickel (each Within a margin of one per cent higher or lower) chromium twenty-six per cent and nickel twentyefive per cent, with from one to three and one-half per cent of silicon.

lriltesimony whereof I have hereunto set an CHAR-LES MORRIS JOHNSON. 

